Investigations on the effect of different influencing factors on film cooling effectiveness under the injection of synthetic coolant

Abstract

By combining the synthetic jet and film cooling, the incident cooling flow is specially treated to find a better film cooling method. Numerical simulations of the synthetic coolant ejected are carried out for analyzing the cooling performance in detail, under different blowing ratios, hole patterns, Strouhal numbers, and various orders of incidence for the two rows of holes. By comparing the flow structures and the cooling effect corresponding to the synthetic coolant and the steady coolant fields, it is found that within the scope of the investigations, the best cooling effect can be obtained under the incident conditions of an elliptical hole with the aspect ratio of 0.618, the blow molding ratio of 2.5, and the Strouhal number St = 0.22. Due to the strong controllability of the synthetic coolant, the synthetic coolant can be controlled through adjusting the frequency of blowing and suction, so as to change the interaction between vortex structures for improving film cooling effect in turn. As a result, the synthetic coolant ejection is more advisable in certain conditions to achieve better outcomes.

Contribution of Different Parameters on Film Cooling Efficiency Based on the Improved Orthogonal Experiment Method

“…Film cooling provides thermal protection to the blade metal wall and downstream of the hole by injecting colder air on the outer surface, forming an insulating layer between the hot main flow and also the surface to be cooled, thereby reducing heat transfer to the surface [12][13][14]. Film cooling technology has been widely used in various fields, such as aerospace, and optimizing gas-film cooling systems is mainly focused on in the investigations.…”